Detection Threshold of the Height Difference between a Visual and Physical Step

In recent years, virtual reality (VR) applications that accompany real-space walking have become popular. In these applications, the expression of steps, such as a stairway, is a technical challenge. Preparing a real step with the same scale as that of the step in the VR space is one alternative; however, it is costly and impractical. We propose using a real step, but one physical step for the expression of various steps, by manipulating the viewpoint and foot position when ascending and descending real steps. The hypothesis is that the height of a step can be complemented to some extent visually, even if the heights of the real step and that in the VR space are different. In this paper, we first propose a viewpoint and foot position manipulation algorithm. T hen we measure the detection threshold of the height difference between the visual and physical step when ascending and descending the physical step using our manipulation algorithm. As a result, we found that the difference can be detected if there is a difference of approximately 1.0 cm between the VR space and the real space, irrespective of the height of the physical step.